An ONA (Open Network Adaptor) printed board is an extension board inserted into a channel slot within a housing of a server, the ONA mounted thereon, which is defined as a LAN adaptor for establishing a connection with Ethernet (the registered trademark of Fuji Xerox Co. Ltd.), is connected to a plurality of terminals via the network and supports open network protocols such as TCP/IP, OSI and FNA (Fujitsu Network Architecture). Note that the server housing is mounted with, in addition, a service processor (SVP) as a dedicated processor which manages setting information and performs initial diagnosis of the server and monitors an operation status ranging from switching ON a power source to switching OFF the power source.
The ONA described above generates a MAC frame by attaching information such as a destination MAC address and a MAC address of the ONA itself to the communication data received from the server and broadcasts the thus-generated MAC frame to the network. Moreover, the ONA extracts the data from the MAC frame of which the destination MAC address is coincident with the self MAC address among the MAC frames received from the respective terminals via the network, and hands over the extracted data to the server. Therefore, a unique MAC address is allocated to each ONA printed board when shipped from a factory and is written to a memory (EEPROM) on the ONA printed board.
A scheme of the ONA printed board used for the server is, however, not that the MAC address written to the EEPROM is read in an intact status and used for transmitting and receiving the data but that the SVP reads the MAC address from the EEPROM of the ONA printed board mounted for the first time into the housing of the server and stores the MAC address in a hard disk, and the MAC address is hereafter copied to an SDRAM on the ONA printed board mounted in the housing of the server and used for the ONA of the ONA printed board to transmit and receive the data.
The reason why such MAC address management is carried out is derived from the following. Namely, the terminal using the MAC address for the communications with the ONA in the server includes an ARP table for ARP (Address Resolution Protocol) and is required to set the MAC address of the ONA and an IP address of the server in the way of being associated with each other. Accordingly, if the MAC address written to the EEPROM of the ONA printed board is used in an intact status similarly to the management in a small-scale computer using a general type of LAN card, the MAC address in the ARP table of the individual terminal must be reset each time the ONA printed board is replaced from within the housing of the server. Restraint of a downtime of the ONA down to the minimum when a fault occurs in, e.g., the ONA printed board, however, entails replacing the whole ONA printed board, and, while on the other hand, since the terminals performing the communications with the server tremendously rise in number, it is desirable for reducing a time-consuming operation for maintenance of the whole system that the resetting of the MAC address on the terminal is made unnecessary. Therefore, the operation of copying the MAC address stored in the hard disk of the SVP described above to the SDRAM on the ONA printed board and thus using the MAC address, is adopted.
An in-depth description of the operation of the MAC address described above will hereinafter be made with reference to FIGS. 20 through 23.
To start with, in a flowchart of FIG. 20 illustrating an operation flow when newly mounting, a person in charge of maintenance (customer engineer) begins a mounting work (S501) and mount the ONA printed board into the housing of the server. Then, a CPU on the ONA printed board detects that the ONA printed board is mounted in a housing A (S521), whereby the SVP starts the mount process (S511). And the SVP reads the MAC address (MAC address A), which is unique to the ONA printed board, from the EEPROM of the ONA printed board (S512), and stores the MAC address in the hard disk (S513). On the other hand, the CPU on the ONA printed board sets the flag of the EEPROM to “invalid”, thereby invaliding the MAC address A (S522). With the processes described above, the mount process by the ONA printed board and the mount process of the SVP are completed.
Subsequently, the customer engineer sets the MAC address A in the ARP table of each of the terminals performing the communications with the server.
Hereafter, when a user of the server switches ON a main power source, an initial setting process is executed, and the MAC address A stored in the hard disk of the SVP is copied to the SDRAM of the ONA printed board and used for the ONA to transmit and receive the data.
Next, when the customer engineer inputs the exchange instruction to the SVP from on the console, the SVP starts the exchange process (S621) and enables the ONA printed board (old ONA) to be demounted (S622). Then, the customer engineer demounts the old ONA from the housing A. Subsequently, the customer engineer mounts the ONA printed board (new ONA) of which a MAC address B is written in the EEPROM (FIG. 21). Thereupon, the CPU of the ONA printed board with the new ONA detects that the ONA printed board (ONA) is mounted into the housing A (S631) and, after notifying the SVP that the new ONA is mounted (S632), sets the flag of the EEPROM to “invalid”, thereby invalidating the MAC address B (S633, FIG. 22). On the other hand, the SVP receiving the notification notifies, through the console, the customer engineer of the completion of mounting the new ONA (S623). With the processes described above, the mount process by the ONA printed board and the exchange process of the SVP are completed.
Through the processes described above, the MAC address A stored in the hard disk of the SVP is not changed. Further, the MAC address A set in the ARP table of each terminal is not changed. Hence, hereafter, when the user of the server switches ON the main power source, the initial setting process is executed, and the MAC address A stored in the hard disk of the SVP is copied to the SDRAM of the ONA printed board and used for the ONA to transmit and the receive the data.
Note that, if the flag on the EEPROM of the ONA printed board is set to “invalid”, the readout of the MAC address from the EEPROM is inhibited. And “invalid” is set to the flag of the EEPROM of the ONA printed board for the old ONA (FIG. 23). Therefore, it does not happen, as long as the value of the flag remains “invalid”, that the MAC address A unique to the ONA printed board, which is written to the EEPROM, is read even when the ONA printed board for the old ONA is demounted from the housing A and inserted into another housing (housing B). This contrivance prevents the uniqueness of the MAC address from being affected due to an overlap of the MAC address between the housing A and the housing B.    [Patent document 1] Japanese Laid-Open Patent Publication No. H10-65702    [Patent document 2] Japanese Laid-Open Patent Publication No. 2004-13327    [Patent document 3] Japanese Laid-Open Patent Publication No. 2005-51527
The operation example of the MAC address described above is applied to the case of exchanging only the ONA printed board without exchanging the housing of the server, however, in the case of purchasing a server system including the housing and replacing the server system within the conventional housing, it is desirable in terms of an economic aspect that the ONA printed board is migrated into the new housing (housing B) and thus utilized unless any fault occurs in the ONA printed board. In this case, if the ONA printed board can successively utilize the MAC address A employed so far in the original housing (housing A), it is convenient because of having no necessity for changing the setting in the ARP table of each terminal.
The MAC address A is not, however, stored from the beginning in the hard disk of the SVP in the new housing (housing B). Further, as described above, “invalid” is set to the flag on the EEPROM of the ONA printed board which is once mounted into the original housing (housing A), and hence, if the ONA printed board once mounted into the original housing is mounted into the new housing (housing B), it does not happen the MAC address A is read from the EEPROM and stored in the hard disk of the SVP. Note that the customer engineer should be assigned neither authority of deleting the MAC address on the hard disk of the SVP nor authority of changing the flag of the EEPROM of the ONA printed board in order to keep the uniqueness of the MAC address and is therefore disabled from manually changing the flag.
Moreover, on the EEPROM of the ONA printed board mounted into the original housing (housing A) in place of the old ONA printed board, the unique MAC address B different from the MAC address A used so far in the original housing (housing A) is written. Therefore, if the board with mounting even if the value of the flag can be changed to “valid”, the MAC address A can not be handed over to the new housing (housing B).
Under such circumstances, in the status quo, it is impossible to take over the MAC address, and, as a result, if the housing of the server is changed, a necessity inevitably arises for resetting the MAC address in the ARP tables of all of the terminals performing the communications with the server.